First disaster - snapped hood bolt

[GT Pony]

It's not the torque value it's the length of the wrench and the leverage that snapped the bolt

Lever arm x force = torque. If torque didn't snap it, don't know what did.

Sponsored

 

[DougS550]

It's not the torque value it's the length of the wrench and the leverage that snapped the bolt

Great to hear. Have Fun

 

[Norm Peterson]

NOW: A piece of advice, get a inch pound torque wrench for the little bolts. Believe me it will save you more head aches.

This ^^^


Norm

 

[65straight6]

Why would you use a torque wrench? It's not a head bolt. A little thread-lock and tighten just enough.

Maybe too late for this advice??

 

[Norm Peterson]

Why would you use a torque wrench? It's not a head bolt.

The only real difference between head bolts and hood bolts is that hood bolts are not required to provide pressure vessel integrity. Peak cylinder pressures can reach 1000 psi, or (momentarily) about 10,000 lbs on the head above the firing cylinder trying to lift it clear every time a cylinder in that bank fires.

Hood bolts still need to provide enough clamp load to guard against joint slippage (if not tight enough) without trying for so much clamp load that you get into fastener failure (like we have here). For small fasteners, there's only a narrow range between the two in absolute terms.


Norm

 

[DougS550]

The only real difference between head bolts and hood bolts is that hood bolts are not required to provide pressure vessel integrity. Peak cylinder pressures can reach 1000 psi, or (momentarily) about 10,000 lbs on the head above the firing cylinder trying to lift it clear every time a cylinder in that bank fires.

Hood bolts still need to provide enough clamp load to guard against joint slippage (if not tight enough) without trying for so much clamp load that you get into fastener failure (like we have here). For small fasteners, there's only a narrow range between the two in absolute terms.


Norm

Please don't relate the torquing of specialized bolts, torsion, shear stretch ETC with common bolts like the hood bolts ETC. Zero relationship or similarities. You want to use a foot pound torque wrench on none special bolts is totally up to you if that makes you feel more comfortable. No one's trying to bust your chops, just trying to give a little FYI help. Good Luck

 

[Dr. Norts]

Please don't relate the torquing of specialized bolts, torsion, shear stretch ETC with common bolts like the hood bolts ETC. Zero relationship or similarities. You want to use a foot pound torque wrench on none special bolts is totally up to you if that makes you feel more comfortable. No one's trying to bust your chops, just trying to give a little FYI help. Good Luck

Everything has a tq value whether its a tiny screw or a giant bolt and everything in between. Torquing all fasteners is proper practice and there's nothing wrong with that.

Using a 3/8" or 1/2" drive tq wrench that's in ft/lbs will tend to snap bolts less than 10 ft/lbs on occasion.

I don't know why but the length of the wrench combined with a low torque setting will make the wrench not click and then snap goes the stud or bolt.

For anything 10-12 ft/lbs or less get yourself a small 1/4 drive in/lbs tq wrench and I promise that will never happen again. Especially when dealing with 6-8mm threads and studs like the trunk / hood mounts.

 

[Zelek]

Add me to the list. Installing hood struts and hand tightened on the driver's side followed by a snap. Can this be fixed with a TIG weld and work with the original nut?

 

[Semp1]

Add me to the list. Installing hood struts and hand tightened on the driver's side followed by a snap. Can this be fixed with a TIG weld and work with the original nut?

It’s an unimportant bolt even if it can’t. That bolt does nothing to support the hood. That’s why the strut goes there. Go to a reliable shop or welder see if you can get it fixed. If you can’t reinstall the prop rod use touch up on it and forget about it.

 

[Sig556]

I have a 1/4 inch drive INCH POUND torque wrench. Convert your 10 ft lb to inch pounds and you are good to go. OR just carefully snug up the nut with a hand wrench. Either way you should be safe. Why in Hell does Ford cheap out and use such worthless fasteners is anyone's guess.

 

[thunderstrike]

You can get a broken bolt extractor for cheap and remove it. Get new bolts from Home Depot or Lowe's, you'll be set.

 

[Firsttexan]

That bolt had issues before you snapped it. Notice it's almost rusted to the center.
With two people you can remove the other bolt and then use vise grips to remove.

Otherwise Remove the hood and lay it down on a soft surface. A pair of vice grips should do the job. Doing it on the car is a pain and could damage and scratch things.

 

[Zelek]

Considering a new solution. Although I got the thread welded back on, it's not the most ideal solution for me. I had to use washers to make up the gap for the nut to fit back on. I'm looking at doing Rivnuts on all 4 bolts on the hood with some M6 bolts probably. Not sure anyone has tried this or attempted it yet.

 

[DougS550]

I use rivet nuts everywhere. But the right ones have to be used for it's location to prevent damage. I use regular expanding rivet nuts when going into a steel hole with an ID which meets the expansion ID requirements. I use the ones which pull the bottom up tight against the back side of the thin panel, plastic panel CF panel ect. All 6mm x 1.0. good luck.

 

[Zelek]

I use rivet nuts everywhere. But the right ones have to be used for it's location to prevent damage. I use regular expanding rivet nuts when going into a steel hole with an ID which meets the expansion ID requirements. I use the ones which pull the bottom up tight against the back side of the thin panel, plastic panel CF panel ect. All 6mm x 1.0. good luck.

Yeah, wondering if I need to use some M6 aluminum ones. I've never done Rivnuts myself but I see them everywhere. I want to fix the flimsy cheap studs in the hood and if I fix one, I may as well do all 4 while the hood is off.

Sponsored